Input: ili210x - add DT binding document

Add DT binding document for the Ilitek ILI210x and ILI251x
touchscreen controllers.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
1 file changed